Wolf G, Müller N, Mandecka A, Müller U A
Clinic for Internal Medicine Ill, University Clinic, Friedrich Schiller University Jena, Germany.
Clin Nephrol. 2007 Aug;68(2):81-6. doi: 10.5414/cnp68081.
It takes years for microvascular complications in diabetes mellitus such as diabetic retinopathy (RP) and nephropathy (NP) to develop. Since retinal and renal vessels are exposed to the diabetic milieu, it is often assumed that progression of diabetic RP and NP occurs at the same time. However, smaller studies have demonstrated that this may not always be the case. The present study was undertaken to correlate diabetic retinopathy with parameters of renal function in a large ambulatory collective of patients with Types 1 and 2 diabetes.
The study design was cross-sectional. Ambulatory patients from a large university out-patient clinic were studied (323 patients with Type 1, 906 patients with Type 2 diabetes). RP status was obtained through retinal photography by an experienced ophthalmologist and was grouped into no RP, RP Stages 1-3, or blind. Retinal pathology was correlated with clinical parameters of renal function (proteinuria, estimated glomerular filtration rate according to the MDRD formula, presence of urinary sediment abnormalities, hypertension).
No patient showed urinary sediment abnormalities (e.g. presence of hematuria or acanthocytes) or increased urinary excretion of immunoglobulin light chains suggesting the absence of other nondiabetic renal diseases. The majority of Type 1 diabetes patients with macroalbuminuria (> or = 200 mg/l) had some signs of RP independent of the presence of hypertension. There was a correlation between RP and microalbuminuria (r = 0.164, p < 0.01). In contrast, up to 47.5% of the hypertensive patients with Type 2 diabetes and overt proteinuria had no signs of RP. There was also discordance of microalbuminuria and RP in patients with Type 2 diabetes. Stratification according to K/DOQI States 2-5 (MDRD formula) showed that the majority of patients with Type 1 diabetes in States 3-5 had signs of RP, albeit the absolute number of patients in these K/DOQI stages was very small. In contrast, up to 40% of dialysis-dependent Type 2 diabetics (K/DOQI State 5) showed no evidence of RP.
This study revealed that many patients with Type 2 diabetes and renal abnormalities (proteinuria and/or renal insufficiency) showed, in contrast to Type 1 diabetics, no signs of RP. Our study was, however, limited by the lack of renal biopsies. Although urinary sediment analysis was normal in these patients, other causes for renal insufficiency (e.g. vascular nephropathy), especially in Type 2 diabetics, cannot be excluded. Nevertheless, we believe that absence of RP in patients with Type 2 diabetes does not imply that renal abnormalities including diabetic nephropathy, are also absent. It is recommended that these patients undergo renal biopsy.
糖尿病微血管并发症如糖尿病视网膜病变（RP）和肾病（NP）的发展需要数年时间。由于视网膜和肾血管暴露于糖尿病环境中，人们通常认为糖尿病RP和NP的进展是同时发生的。然而，一些较小规模的研究表明情况可能并非总是如此。本研究旨在对一大组1型和2型糖尿病门诊患者的糖尿病视网膜病变与肾功能参数进行相关性研究。
本研究设计为横断面研究。对一所大型大学门诊的门诊患者进行研究（323例1型糖尿病患者，906例2型糖尿病患者）。由经验丰富的眼科医生通过视网膜摄影确定RP状态，并分为无RP、RP 1 - 3期或失明。视网膜病变与肾功能的临床参数（蛋白尿、根据MDRD公式估算的肾小球滤过率、尿沉渣异常的存在、高血压）进行相关性分析。
没有患者出现尿沉渣异常（如血尿或棘形红细胞的存在）或免疫球蛋白轻链尿排泄增加，提示不存在其他非糖尿病性肾脏疾病。大多数有大量蛋白尿（≥200mg/l）的1型糖尿病患者有一些RP体征，与高血压的存在无关。RP与微量白蛋白尿之间存在相关性（r = 0.164，p < 0.01）。相比之下，高达47.5%的2型糖尿病高血压患者伴有显性蛋白尿却没有RP体征。2型糖尿病患者中也存在微量白蛋白尿与RP不一致的情况。根据K/DOQI 2 - 5期（MDRD公式）分层显示，3 - 5期的大多数1型糖尿病患者有RP体征，尽管这些K/DOQI分期中的患者绝对数量很少。相比之下，高达40%的依赖透析的2型糖尿病患者（K/DOQI 5期）没有RP证据。
本研究表明，与1型糖尿病患者相比，许多有肾脏异常（蛋白尿和/或肾功能不全）的2型糖尿病患者没有RP体征。然而，我们的研究受到缺乏肾活检的限制。尽管这些患者的尿沉渣分析正常，但不能排除肾功能不全的其他原因（如血管性肾病），尤其是在2型糖尿病患者中。尽管如此，我们认为2型糖尿病患者没有RP并不意味着也不存在包括糖尿病肾病在内的肾脏异常。建议这些患者进行肾活检。
